Zdorovʹe Rebenka (Sep 2017)
The features of influenza course in children in epidemic season of 2016–2017
Abstract
Background. One of the widespread acute respiratory viral infections is influenza. During periods of epidemic recovery, the morbidity increases to 25 %. The highest prevalence of influenza is observed among children. The seriousness of the problem is determined not only by the high morbidity of influenza, which often take form of epidemics and pandemics, but also by the risk of developing severe complications with frequent lethal outcomes. The purpose of the research was to analyze the respiratory morbidity of children for the period from 2009 to 2017, and to study clinical and laboratory features of influenza in the past epidemic season of 2016–2017. Materials and methods. 335 medical records of children with acute respiratory viral infection (ARVI) and influenza for the period from November 2016 to March 2017 were analyzed. Virological investigations were carried out by polymerase chain reaction and enzyme-linked immunoassay in virological laboratory of Dnipropetrovsk region laboratory center of MH of Ukraine. The research was conducted using the sampling method, taking into account the characteristics of the clinical pattern of respiratory disease and the time of admission to a hospital from the onset of the disease. Results. The analysis of the morbidity of influenza and ARVI for the period from 2009 to 2017 made it possible to distinguish early increases in the incidence of influenza in 2009–2010 and in the past epidemic season of 2016–2017. During the seasons of 2012–2013 and 2013–2014, an increase of ARVI and influenza morbidity was observed in March. In the season of 2016-17, the higher morbidity of influenza was detected among toddlers and schoolchildren. Only in 24 (26.6 %) out of 90 children with clinically suspected influenza, a positive result of virological study was received. The diagnosis of influenza A/H3N2 was confirmed in most of the examined children (24.4 %) and influenza B — in 2.2 % children. The typical for influenza symptoms of intoxication, fever, catarrhal symptoms were observed in the clinical picture. The hyperthermia was within 38–39 °C in most children (46.2 % cases). However, almost one third of children (35.1 %) had high and hyperpyretic fever, which indicated a severe influenza. We noted that a more expressed intoxication syndrome was observed in children of senior school age. Symptoms of typical influenza intoxication in young children were absent or were not so critical. Catarrhal syndrome was identified only in 85 % of children. In 11.7 % of cases, the symptoms of a digestive tract lesion in the form of vomiting (8.2 %), nausea (1.2 %), abdominal pain (2.3 %) were observed. The complicated course of influenza was characterized by involvement of convulsive syndrome and the lower respiratory tract infection in the form of bronchitis and pneumonia. In the age group from 1 to 3 years, convulsive syndrome was observed in 5 children (5.5 %) with high fever. In the group of preschool children, the course of influenza infection was complicated by the development of bronchitis in 3.6 % of the examined children. The severe course of influenza led to the development of pneumonia in 5.4 % of patients. Pneumonia was mainly observed in children of senior school age and was characterized by a low-symptomatic clinical picture. Conclusions. The study made it possible to note the following features of the epidemic season of 2016–2017: early onset of the active influenza period from November; dominance of influenza A/H3N2; less aggressive course of influenza (moderate forms). Complicated course of influenza A/H3N2 was more often observed in the age groups of schoolchildren and young children. The severe course of influenza infection was characterized by prolonged high fever, as well as the involvement of convulsive syndrome and the lesion of the lower respiratory tract. The feature of the influenza infection course in young children was the absence of specific symptoms, which made it difficult to diagnose the flu early and to assess the risk of a complicated course of the disease.
Keywords
